Ellis, now 34, had a stellar run with the Athletics. He came within a game’s worth of plate appearances from reaching 4,300 trips to the plate in his A’s career, and hit .265/.331/.397 in those he did amass. Once park factors are considered, that line becomes a little more impressive. Offense was never Ellis’ forte anyways, but defensively, the man could pick it. No second baseman in baseball has as many fielding runs above average since the 2002 season as Ellis—who holds a three-run lead over Orlando Hudson, the two of whom are separated from the pack by nearly 10 runs.

Rather than sticking his toe into the free agent waters after the 2008 season, Ellis decided to re-sign with the Athletics. At the time, the decision drew ire. After all, why should Ellis, the best defensive second baseman in baseball, forego the chance to get market value (or above) in place of a team-friendly contract? But re-signing spoke to the connection Ellis felt with Oakland, or if nothing else, the relationship between player and team.

Injuries and aging have taken their toll, and in the two and a half seasons since, the Athletics have paid Ellis $15.5 million (as Colorado is only on the tab for $1 million) for 3.6 wins above replacement player—or $4.3 million per win. Compare that to the aforementioned Hudson’s performance and salaries over the same span (5.6 WARP for $12.4 million), and perhaps the Athletics could have been more efficient by letting Ellis walk. Alas, that knowledge only comes with the gift of hindsight.

As for the known piece of the return, Billings made his major league debut in late May, appearing in one game, completing two innings, and giving up five hits on 38 pitches. At 6-foot, 200 pounds, Billings is a short righty who relies on a low-90s fastball and solid slider to get work done. Billings is already 25, and turns 26 in late November, so the upside appears limited. His work in Triple-A this season has not been inspiring either, with a 2.24 strikeout-to-walk ratio and 4.47 earned run average, but it is the Pacific Coast League and those numbers might be skewed upwards.

There is a bright side to the deal for A’s fans, however bittersweet it may be, as Jemile Weeks figures to become the team’s starting second baseman for the next few seasons.

Colorado Rockies
Traded RHP Bruce Billings and a player to be named later to the Athletics for 2B-R Mark Ellis and cash. [6/30]

The Rockies have had a hellacious time figuring out who to play at the keystone and hot corner this season—as those are the only offensive positions that have not produced an OPS over 700 for Colorado. Ellis isn’t going to raise the bar much, as PECOTA projects a .246/.309/.343 line from here on out, but keep in mind that he has hit .265/.317/.370 since 2009, with most of that coming in Oakland’s spacey ballpark, which is also the basis for the projection. Coors Park isn’t the offensive paradise it once was, but the hitting experience in Colorado and Oakland are still closer to polar opposites than twins.

At the price of $1 million, a middle relief prospect, and a player to be named later, the Rockies get a veteran second baseman that can still field the position and might have a little more offense left in him than his season-to-date numbers suggest. The downsides—Ellis’ injury history and the potential that he is cooked—are negated given the transaction and opportunity costs at play. Colorado has flipped through Jonathan Herrera and Chris Nelson over the last few weeks, and evidently felt the need to go out and get another option, even if it represents only a marginal upgrade in their eyes.

There are certain to be some qualitative reasons too. Ellis has playoff experience and all the rest of the buzzwords teams look for in potential blasé veteran additions at this point in the season. Acquiring Ellis is not the sexiest move for a team 6 1/2 games out of first place, but it is the one the Rockies pursued, and one unlikely to burn them.

Surely NOT a good move for the Rox, since it is not clear Ellis provides an upgrade over either of their existing alternatives. He is not the player he was, and has less upside than what they have already.